Determine whether the intitial use of two non-nucleoside reverse transcriptase inhibitors (NRTIs) plus Nelfinavir followed by a different two NRTIs plus Efavirenz is superior to the initial use of two NRTIs plus Efavirenz followed by a different two NRTIs plus Nelfinavir. Determine whether initial use of two NRTIs plus Nelfinavir plus Efavirenz is superior to either of the two consecutive 3-drug regimens, and determine whether 3TC/ZDV followed by ddI + d4T is superior to ddI + d4T followed by 3TC/ZDV when these NRTI combinations are taken with Nelvinavir or Efavirenz.